precision highp float;
uniform vec2 u_resolution;
void main(){
    vec2 vUv = gl_FragCoord.xy / u_resolution;
    vec3 line=vec3(1,1,0);
    float d=abs(cross(vec3(vUv,0),normalize(line)).z);
    gl_FragColor.rgb=(1.-smoothstep(0.,.01,d))*vec3(1.);
    gl_FragColor.a=1.;
}